Four people were arrested yesterday in connection with a police investigation into alleged slavery.

Detectives are also investigating an anonymous tip that a worker may have been buried on a farm, with forensic archaeologists called in to examine a plot.

More than 100 officers from Gwent Police raided three addresses around Newport in South Wales in the early hours after a long-running operation into workers being kept in “slave conditions” without pay. Two men, aged 66 and 42, from Marshfield, near Newport, a man, 36, of Cardiff and a woman, 42, of Penhow, Monmouthshire, were arrested. An Eastern European man